(1) Technical Field
The present invention relates to energy absorbers with anti-buzz, squeak and rattle (“BSR”) accessories. The energy absorbers and associated accessories are interposed between for example a vehicular outer skin and an interior structure such as a headliner. The energy absorbers and accessories are provided in automotive and non-automotive applications.
(2) Background Art
Vehicle manufacturers spend considerable time and effort to eliminate buzz/squeak/rattle (“BSR”) noises because they can be irritating and annoying to vehicle drivers and passengers, particularly when the BSR noises come from a location close to a passenger's head, and/or any component in the vehicle's passenger compartment, especially when the noises are created near or are amplified by components that effectively form an echo chamber.
Several shaped thermoformed energy absorbers are known, such as those described in U.S. Pat. Nos. 6,017,084; 6,221,292; 6,199,942; 6,247,745; 6,679,967; 6,682,128; 6,752,450; 7,360,822; 7,377,577; 7,384,095; and 7,404,593. These absorbers are said to provide dynamic reaction force characteristics that produce a relatively “square wave” characteristic when observing their reaction force properties as a function of deflection. But such absorbers lack effective anti-BSR features.
U.S. Pat. No. 8,465,087 describes a formed energy absorber with an integrated anti-BSR feature which includes a protrusion that suppresses or dampens buzzes, squeaks or rattles at the end wall of an energy absorbing structure. Such structures typically lie between a Class-A surface (such as a bumper fascia, a headliner, or a door trim panel) and a rigid sheet metal structure in automotive applications. The absorber is typically installed with a 3-5 mm gap from one surface and is attached to another. However, in some instances it becomes necessary to reduce the gap to improve the reaction response time at the primary area of impact prior to secondary impacts, as for example when the head hits adjacent structures. When the absorber contacts the opposing surface, an undesirable buzz or rattle can be heard. This noise occurs because a flat hard plastic surface can tap or vibrate against the opposing structure.
The '087 patent describes an anti-BSR feature that is made integrally with an associated energy absorber during the thermoforming process. However, this feature has proven difficult to form consistently, requires relatively a narrow processing window, and generally lacks the flexibility necessary to fully mitigate the translation of one structure to another that creates a BSR condition.
Materials such as foam, felt, and flock are often added to absorbers which lack an integrated structure to remedy the BSR issue. A fabric pad, flock material, foam padding, or some other kind of flexible material if added to one of the surfaces responsible for making the noise may lessen or eliminate the severity of the buzzing or tapping or eliminate the possibility of one surface translating into the other. However, this solution requires the purchase and assembly of one or more separate components, and that results in added complexity, cost, and mass.